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PubMed2005

Attentional inhibition has social-emotional consequences for unfamiliar faces.

Visual attention studies often rely on response time measures to show the impact of attentional facilitation and inhibition. Here we extend the investigation of the effects of attention on behavior and show that prior attentional states associated with unfamiliar faces can influence subsequent social-emotional judgments about those faces. Participants were shown pairs of face images and were asked to withhold a response if a transparent stop-signal cue appeared over one of the faces. This served to associate the cued face with an inhibitory state. Later, when asked to make social-emotional choices about these face pairs, participants chose uncued faces more often than cued faces as "more trustworthy" and chose cued faces more often than uncued faces as "less trustworthy." For perceptual choices, there was no effect of how the question was framed (which face is "on a lighter background" vs. "on a darker background"). These results suggest that attentional inhibition can be associated with socially relevant stimuli, such as faces, and can have specific, deleterious effects on social-emotional judgments.

Attention↗
PubMed2005

Does prosopagnosia take the eyes out of face representations? Evidence for a defect in representing diagnostic facial information following brain damage.

One of the most impressive disorders following brain damage to the ventral occipitotemporal cortex is prosopagnosia, or the inability to recognize faces. Although acquired prosopagnosia with preserved general visual and memory functions is rare, several cases have been described in the neuropsychological literature and studied at the functional and neural level over the last decades. Here we tested a brain-damaged patient (PS) presenting a deficit restricted to the category of faces to clarify the nature of the missing and preserved components of the face processing system when it is selectively damaged. Following learning to identify 10 neutral and happy faces through extensive training, we investigated patient PS's recognition of faces using Bubbles, a response classification technique that sampled facial information across the faces in different bandwidths of spatial frequencies [Gosselin, F., & Schyns, P. E., Bubbles: A technique to reveal the use of information in recognition tasks. Vision Research, 41, 2261-2271, 2001]. Although PS gradually used less information (i.e., the number of bubbles) to identify faces over testing, the total information required was much larger than for normal controls and decreased less steeply with practice. Most importantly, the facial information used to identify individual faces differed between PS and controls. Specifically, in marked contrast to controls, PS did not use the optimal eye information to identify familiar faces, but instead the lower part of the face, including the mouth and the external contours, as normal observers typically do when processing unfamiliar faces. Together, the findings reported here suggest that damage to the face processing system is characterized by an inability to use the information that is optimal to judge identity, focusing instead on suboptimal information.

Adult↗
PubMed1999

Figural aftereffects in the perception of faces.

We examined figural aftereffects in images of human faces, for which changes in configuration are highly discriminable. Observers either matched or rated faces before or after viewing distorted images of faces. Prior adaptation strongly biases face perception by causing the original face to appear distorted in a direction opposite to the adapting distortion. Aftereffects transferred across different faces and were similar for upright or inverted faces, but were weaker when the adapting and test faces had different orientations (e.g., adapt inverted and test upright). Thus the aftereffects depend on which images are distorted, and not simply on the type of distortion introduced. We further show that the aftereffects are asymmetric, for adapting to the original face has little effect on the perception of a distorted face. This asymmetry suggests that adaptation may play an important normalizing role in face perception. Our results suggest that in normal viewing, figural aftereffects may strongly influence form perception and could provide a novel method for probing properties of human face perception.

Discrimination Learning↗
PubMed2000

Neural systems underlying the recognition of familiar and newly learned faces.

Memory for famous faces can be used to examine the neural systems underlying retrieval from long-term memory. To date, there have been a limited number of functional neuroimaging investigations examining famous face recognition. In this study, we compared recognition of famous faces to recognition of newly learned faces. Whole-brain, event-related functional magnetic resonance imaging was used to image regional changes in neural activity in 11 subjects during the encoding of unfamiliar faces and during familiarity judgments for: (1) newly learned faces, (2) unfamiliar face distractors, and (3) famous faces. Image analyses were restricted to correct recognition trials. Recognition accuracy and response time to famous and recently learned faces were equivalent. Recognition of famous faces was associated with a widespread network of bilateral brain activations involving the prefrontal, lateral temporal, and mesial temporal (hippocampal and parahippocampal regions) regions compared to recognition of recently encoded faces or unfamiliar faces seen for the first time. Findings are discussed in relation to current proposals concerning the neural regions thought to participate in long-term memory retrieval and, more specifically, in relation to retrieval of information from the person identity semantic system.

Adult↗
PubMed1995

[A case of predominantly right-temporal lobe atrophy with disturbance of identifying familiar faces].

A right-handed 72-year-old man (I.K.) who complained of difficulty identifying familiar faces was investigated on a series of tests of face perception (face matching, recognition of age and sex, and meaning of facial expressions), facial identity (faces of families and famous persons as retrograde ones and his doctor's faces as anterograde ones) and other neuropsychological abilities. His scores of face perception tests were normal or mildly disturbed. His memory performances measured with WMS-R and Rey-Osterrieth figure were normal. But he could identify none of anterograde and retrograde faces and failed to experience any familiarity with those faces. In addition, he could not recognize none of voices of family members and a doctor, despite of being able to recognize about the age and sex of voice. On the other hand, he could describe personalities of his family members and doctors, but knew none of famous people. Memory for personal events in the recent and remote past was well preserved, while that for social events was severely disturbed in both past. In addition to impairment of identification of familiar faces, he had severe problems with identifying famous common buildings and animals. He also presented Gogi (word meaning) aphasia and impairment of semantic memory for some common objects. Tyrrell et al. reported a similar case and McNeil et al. examined the patient on covert recognition of face in detail. On their task, he showed no covert effects and they attributed the result to impairment of face recognition units themselves. Their way of thinking seems to give an explanation of I.K.'s disturbance of anterograde and retrograde memory for faces.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed2002

Affective judgments of faces modulate early activity (approximately 160 ms) within the fusiform gyri.

Functional neuroimaging studies have implicated the fusiform gyri (FG) in structural encoding of faces, while event-related potential (ERP) and magnetoencephalography studies have shown that such encoding occurs approximately 170 ms poststimulus. Behavioral and functional neuroimaging studies suggest that processes involved in face recognition may be strongly modulated by socially relevant information conveyed by faces. To test the hypothesis that affective information indeed modulates early stages of face processing, ERPs were recorded to individually assessed liked, neutral, and disliked faces and checkerboard-reversal stimuli. At the N170 latency, the cortical three-dimensional distribution of current density was computed in stereotactic space using a tomographic source localization technique. Mean activity was extracted from the FG, defined by structure-probability maps, and a meta-cluster delineated by the coordinates of the voxel with the strongest face-sensitive response from five published functional magnetic resonance imaging studies. In the FG, approximately 160 ms poststimulus, liked faces elicited stronger activation than disliked and neutral faces and checkerboard-reversal stimuli. Further, confirming recent results, affect-modulated brain electrical activity started very early in the human brain (approximately 112 ms). These findings suggest that affective features conveyed by faces modulate structural face encoding. Behavioral results from an independent study revealed that the stimuli were not biased toward particular facial expressions and confirmed that liked faces were rated as more attractive. Increased FG activation for liked faces may thus be interpreted as reflecting enhanced attention due to their saliency.

Adult↗
PubMed2003

How do rhesus monkeys ( Macaca mulatta) scan faces in a visual paired comparison task?

When novel and familiar faces are viewed simultaneously, humans and monkeys show a preference for looking at the novel face. The facial features attended to in familiar and novel faces, were determined by analyzing the visual exploration patterns, or scanpaths, of four monkeys performing a visual paired comparison task. In this task, the viewer was first familiarized with an image and then it was presented simultaneously with a novel and the familiar image. A looking preference for the novel image indicated that the viewer recognized the familiar image and hence differentiates between the familiar and the novel images. Scanpaths and relative looking preference were compared for four types of images: (1) familiar and novel objects, (2) familiar and novel monkey faces with neutral expressions, (3) familiar and novel inverted monkey faces, and (4) faces from the same monkey with different facial expressions. Looking time was significantly longer for the novel face, whether it was neutral, expressing an emotion, or inverted. Monkeys did not show a preference, or an aversion, for looking at aggressive or affiliative facial expressions. The analysis of scanpaths indicated that the eyes were the most explored facial feature in all faces. When faces expressed emotions such as a fear grimace, then monkeys scanned features of the face, which contributed to the uniqueness of the expression. Inverted facial images were scanned similarly to upright images. Precise measurement of eye movements during the visual paired comparison task, allowed a novel and more quantitative assessment of the perceptual processes involved the spontaneous visual exploration of faces and facial expressions. These studies indicate that non-human primates carry out the visual analysis of complex images such as faces in a characteristic and quantifiable manner.

Animals↗
PubMed1994

Recognition impairments and face imagery.

We investigated face imagery for H.J.A. and P.H., who experience profound difficulties in recognising familiar faces. H.J.A.'s problems involve a perceptual impairment that compromises the integration of features into a coherent representation, and he does not show covert recognition of faces in indirect tests. In contrast, P.H. has shown extensive covert recognition effects, leading to the suggestion that his deficit occurs at a higher level of visual processing than H.J.A.'s. H.J.A. and P.H. were given tasks intended to explore their ability to answer questions that depended on imaging single faces, and on configuration-based or feature-based comparisons of imaged sets of three faces. For all of these face imagery tasks, P.H.'s overall performance was severely impaired. H.J.A., though, showed preserved face imagery when imaging single faces and when making feature-based comparisons between imaged faces. However, when configuration-based comparisons were demanded H.J.A. also showed a severe and stable impairment of face imagery. These observations are inconsistent with the idea that face recognition impairments have a unitary underlying cause and vary only in severity. Instead, they imply multi-stage causation, with the nature of consequent impairments of face imagery being determined by the level at which the recognition deficit arises.

Adult↗
PubMed2004

View-independent coding of face identity in frontal and temporal cortices is modulated by familiarity: an event-related fMRI study.

Face recognition is a unique visual skill enabling us to recognize a large number of person identities, despite many differences in the visual image from one exposure to another due to changes in viewpoint, illumination, or simply passage of time. Previous familiarity with a face may facilitate recognition when visual changes are important. Using event-related fMRI in 13 healthy observers, we studied the brain systems involved in extracting face identity independent of modifications in visual appearance during a repetition priming paradigm in which two different photographs of the same face (either famous or unfamiliar) were repeated at varying delays. We found that functionally defined face-selective areas in the lateral fusiform cortex showed no repetition effects for faces across changes in image views, irrespective of pre-existing familiarity, suggesting that face representations formed in this region do not generalize across different visual images, even for well-known faces. Repetition of different but easily recognizable views of an unfamiliar face produced selective repetition decreases in a medial portion of the right fusiform gyrus, whereas distinct views of a famous face produced repetition decreases in left middle temporal and left inferior frontal cortex selectively, but no decreases in fusiform cortex. These findings reveal that different views of the same familiar face may not be integrated within a single representation at initial perceptual stages subserved by the fusiform face areas, but rather involve later processing stages where more abstract identity information is accessed.

Adult↗
PubMed2006

The representation of information about faces in the temporal and frontal lobes.

Neurophysiological evidence is described showing that some neurons in the macaque inferior temporal visual cortex have responses that are invariant with respect to the position, size and view of faces and objects, and that these neurons show rapid processing and rapid learning. Which face or object is present is encoded using a distributed representation in which each neuron conveys independent information in its firing rate, with little information evident in the relative time of firing of different neurons. This ensemble encoding has the advantages of maximising the information in the representation useful for discrimination between stimuli using a simple weighted sum of the neuronal firing by the receiving neurons, generalisation and graceful degradation. These invariant representations are ideally suited to provide the inputs to brain regions such as the orbitofrontal cortex and amygdala that learn the reinforcement associations of an individual's face, for then the learning, and the appropriate social and emotional responses, generalise to other views of the same face. A theory is described of how such invariant representations may be produced in a hierarchically organised set of visual cortical areas with convergent connectivity. The theory proposes that neurons in these visual areas use a modified Hebb synaptic modification rule with a short-term memory trace to capture whatever can be captured at each stage that is invariant about objects as the objects change in retinal view, position, size and rotation. Another population of neurons in the cortex in the superior temporal sulcus encodes other aspects of faces such as face expression, eye gaze, face view and whether the head is moving. These neurons thus provide important additional inputs to parts of the brain such as the orbitofrontal cortex and amygdala that are involved in social communication and emotional behaviour. Outputs of these systems reach the amygdala, in which face-selective neurons are found, and also the orbitofrontal cortex, in which some neurons are tuned to face identity and others to face expression. In humans, activation of the orbitofrontal cortex is found when a change of face expression acts as a social signal that behaviour should change; and damage to the orbitofrontal cortex can impair face and voice expression identification, and also the reversal of emotional behaviour that normally occurs when reinforcers are reversed.

Animals↗
PubMed1999

Human face perception traced by magneto- and electro-encephalography.

The temporal and spatial processing of face perception in normal subjects was traced by magnetoencephalography (MEG) and electroencephalography (EEG). We used 5 different visual stimuli: (1) face with opened eyes, (2) face with closed eyes, (3) eyes, (4) scrambled face, and (5) hand, and they were shown in random order. Subjects were asked to count the number of hand stimuli. To analyze the complicated brain responses to visual stimuli, we used brain electric source analysis (BESA) as the spatio-temporal multiple source model. In MEG recording, the 1M and 2M components were identified in all subjects. The 1M component was recorded to all kinds of stimuli. The 2M component was clearly identified only to face stimulation in all subjects, but to eyes stimulation in only 3 subjects with a small amplitude. The 2M component was not identified to scrambled face nor hand stimulation. The 2M component was recorded from the right hemisphere in all subjects, but in only 5 of 10 subjects from the left hemisphere. The mean peak latencies of the 1M and 2M components were approximately 132 and 179 ms, respectively. The interpeak latency between 1M and 2M was approximately 47 ms on average but the interindividual difference was large. There was no significant difference of the 2M latency between face with opened eyes and face with closed eyes. The 1M component was generated in the primary visual cortex in the bilateral hemispheres, and the 2M component was generated in the inferior temporal cortex, around the fusiform gyrus. In the EEG recording, face-specific components, positive at the vertex, P200 (Cz), and the negative at the temporal areas, N190 (T5') and N190 (T6'), were clearly recorded. The EEG results were fundamentally compatible with the MEG results. The amplitude of the component recorded from the right hemisphere was significantly larger than that from the left hemisphere. These findings suggest that the fusiform gyrus is considered to play an important role in face perception in humans, and that the right hemisphere is more dominant. Face perception takes place approximately 47 ms after the primary response to visual stimulation in the primary visual cortex, but the period of information transfer to the fusiform gyrus is variable among subjects. Detailed temporal and spatial analyses of the processing of face perception can be achieved with MEG.

Adult↗
PubMed2005

Attractiveness of own-race, other-race, and mixed-race faces.

Averaged face composites, which represent the central tendency of a familiar population of faces, are attractive. If this prototypicality contributes to their appeal, then averaged composites should be more attractive when their component faces come from a familiar, own-race population than when they come from a less familiar, other-race population. We compared the attractiveness of own-race composites, other-race composites, and mixed-race composites (where the component faces were from both races). In experiment 1, Caucasian participants rated own-race composites as more attractive than other-race composites, but only for male faces. However, mixed-race (Caucasian/Japanese) composites were significantly more attractive than own-race composites, particularly for the opposite sex. In experiment 2, Caucasian and Japanese participants living in Australia and Japan, respectively, selected the most attractive face from a continuum with exaggerated Caucasian characteristics at one end and exaggerated Japanese characteristics at the other, with intervening images including a Caucasian averaged composite, a mixed-race averaged composite, and a Japanese averaged composite. The most attractive face was, again, a mixed-race composite, for both Caucasian and Japanese participants. In experiment 3, Caucasian participants rated individual Eurasian faces as significantly more attractive than either Caucasian or Asian faces. Similar results were obtained with composites. Eurasian faces and composites were also rated as healthier than Caucasian or Asian faces and composites, respectively. These results suggest that signs of health may be more important than prototypicality in making average faces attractive.

Asian People↗
PubMed2002

Gaze behavior of children with pervasive developmental disorder toward human faces: a fixation time study.

BACKGROUND: The abnormal gaze behavior of autistic children toward human faces, as observed in daily-life situations, are investigated in two fixation time studies. It has been argued that faces are a special kind of stimuli for normal individuals and that this might not be the case for autistic children. METHODS: A group of high-functioning autistic children (including a group of sub-threshold PDD-NOS children) was compared with a group of normal children, with respect to their fixation behavior for photographs of human faces. Using an infrared eye-tracking device, fixation times for the whole face and for the facial elements of faces were compared between the two groups. The first study dealt with faces having an emotional expression. The second study dealt with neutral faces presented either upright or upside-down. RESULTS: Results of the two studies showed that autistic children have the same fixation behavior as normal children for upright faces, with or without an emotional expression. Furthermore, results of the second study showed that normal children spent less time looking at upside-down faces, but that the fixation times of autistic children were not influenced by the orientation of the faces. CONCLUSIONS: These results plead against the notion that the abnormal gaze behavior in everyday life is due to the presence of facial stimuli per se. Furthermore, the absence of a face orientation effect in autistic children might be a reflection of a lack of holistic processing of human faces in autism.

Attention↗
PubMed1982

Asymmetries in moving faces.

One hundred and two right-handed judges viewed a series of 16 frontally displayed moving faces. They reported which side of each face appeared to move more when the faces were seen (a) speaking and (b) performing face exercise (pulling faces). The left-of-the face was judged more mobile than the right at pulling faces, while there was no asymmetry in the judged movement of the speaking face. Viewing conditions (mirror-reversed/normal orientation) affected judgments of exercising faces, but not of speaking faces. There was a leftward bias of judgements of exercising faces, so that a greater left preference when viewing mirror-reversed rather than normally oriented faces. These results are interpreted with reference to explanations of asymmetries in facial expression and interpretation involving notions of cerebral lateralization.

Adolescent↗
PubMed2002

Few intrinsic connections cross the hand-face border of area 3b of New World monkeys.

After long-standing loss of afferents from the hand, the hand representation in area 3b of the somatosensory cortex of monkeys becomes responsive to touch on the face. Because the reactivation of deprived hand cortex by the face inputs could depend on axonal connections across the hand-face border, we determined the extent of such connections in New World marmosets, owl monkeys, and squirrel monkeys. Small injections of anatomic tracers were placed in the hand or the face representations after these representations were identified by microelectrode recordings. The positions of retrogradely labeled neurons were plotted in processed brain sections cut parallel to the brain surface, and their locations were related to anatomic isomorphs of the hand and face representations revealed in adjacent brain sections stained for myelin. In these sections, the hand-face border was clearly visualized as a myelin-poor septum. The intrinsic connections of area 3b labeled by injections in either the hand or face representations were almost completely confined to their respective representation, and very few neurons projected across the border. In addition, neurons in the somatosensory thalamus labeled by injections in either face or hand representations were confined to either VPM, representing the face, or the hand subnucleus of VPL. Thus the reactivation of hand cortex by face stimulation does not depend on a previously existing network of intrinsic cortical connections across the hand-face border, or mismatched thalamocortical projections.

Afferent Pathways↗
PubMed2000

Recognition and sex categorization of adults' and children's faces: examining performance in the absence of sex-stereotyped cues.

The ability of children and adults to classify the sex of children's and adults' faces using only the biologically based internal facial structure was investigated. Face images of 7- to 10-year-old children and of adults in their 20s were edited digitally to eliminate hairstyle and clothing cues to sex. Seven-year-olds, nine-year-olds, and adults classified a subset of these faces by sex and were asked, subsequently, to recognize the faces from among the entire set of faces. This recognition task was designed to assess the relationship between categorization and recognition accuracy. Participants categorized the adult faces by sex at levels of accuracy varying from just above chance (7-year-olds) to nearly perfect (adults). All participant groups performed less accurately for children's faces than for adults' faces. The 7-year-olds were unable to classify the children's faces by sex at levels above chance. Finally, the faces of children and adults were equally recognizable--a finding that has theoretical implications for understanding the relationship between categorizing and identifying faces.

Adult↗
PubMed2000

Passive and active recognition of one's own face.

Facial identity recognition has been studied mainly with explicit discrimination requirement and faces of social figures in previous human brain imaging studies. We performed a PET activation study with normal volunteers in facial identity recognition tasks using the subject's own face as visual stimulus. Three tasks were designed so that the activation of the visual representation of the face and the effect of sustained attention to the representation could be separately examined: a control-face recognition task (C), a passive own-face recognition task (no explicit discrimination was required) (P), and an active own-face recognition task (explicit discrimination was required) (A). Increased skin conductance responses during recognition of own face were seen in both task P and task A, suggesting the occurrence of psychophysiological changes during recognition of one's own face. The left fusiform gyrus, the right supramarginal gyrus, the left putamen, and the right hypothalamus were activated in tasks P and A compared with task C. The left fusiform gyrus and the right supramarginal gyrus are considered to be involved in the representation of one's own face. The activation in the right supramarginal gyrus may be associated with the representation of one's own face as a part of one's own body. The prefrontal cortices, the right anterior cingulate, the right presupplementary motor area, and the left insula were specifically activated during task A compared with tasks C and P, indicating that these regions may be involved in the sustained attention to the representation of one's own face.

Adult↗
PubMed1996

Using artificial bat sonar neural networks for complex pattern recognition: recognizing faces and the speed of a moving target.

Two sets of studies examined the viability of using bat-like sonar input for artificial neural networks in complex pattern recognition tasks. In the first set of studies, a sonar neural network was required to perform two face recognition tasks. In the first task, the network was trained to recognize different faces regardless of facial expressions. Following training, the network was tested on its ability to generalize and correctly recognize faces using echoes of novel facial expressions that were not included in the training set. The neural network was able to recognize novel echoes of faces almost perfectly (above 96% accuracy) when it was required to recognize up to five faces. In the second face recognition task, a sonar neural network was trained to recognize the sex of 16 faces (eight males and eight females). After training, the network was able to correctly recognize novel echoes of those faces as 'male' or as 'female' faces with accuracy levels of 88%. However, the network was not able to recognize novel faces as 'male' or 'female' faces. In the second set of studies, a sonar neural network was required to learn to recognize the speed of a target that was moving towards the viewer. During training, the target was presented in a variety of orientations, and the network's performance was evaluated when the target was presented in novel orientations that were not included in the training set. The different orientations dramatically affected the amplitude and the frequency composition of the echoes. The neural network was able to learn and recognize the speed of a moving target, and to generalize to new orientations of the target. However, the network was not able to generalize to new speeds that were not included in the training set. The potential and limitations of using bat-like sonar as input for artifical neural networks are discussed.

Adult↗